This invention is concerned with transporting particulate solid material through a pipeline in the form of a slurry and in particular is concerned with transporting coal through a pipeline in the form of a slurry.
It is well recognized that the amounts of recoverable hydrocarbons in the form of crude oil and natural gases are finite and shortages thereof have been experienced. Much consideration has been given to using coal as a substitute for crude oil and natural gas. Large reserves of coal are known to exist in this country. Many of these reserves, however, are located in areas remote from locations where they are desired as fuels. Thus, consideration must be given to transporting coal to remote facilities for use as fuel or of relocating those facilities at the site of the coal deposits.
Coal has been transported from one location to another by trains and barges and to a lesser extent by pipelines. Numerous techniques have been described for transporting coal as a slurry or suspension in a carrier liquid through pipelines.
In U.S. Pat. No. 3,637,263 there is described a method of transporting coal wherein an aqueous slurry is formed of a mixture of particulate coal and an inorganic finely divided water insoluble solid carrier having a specific gravity of at least 1.6 and the slurry is pumped through a pipeline. In U.S. Pat. No. 3,129,164 comminuted coal of a size, for example, of 10 to 200 mesh, is slurried in shale oil and the slurry is subjected to pyrolysis to visbreak the shale oil and to release liquid products from the coal.
In U.S. Pat. No. 3,617,095, bulk solids such as bulk chemicals, grains, coal, and ores are transported through a pipeline by being suspended in a pseudo-plastic or thixotropic fluid exhibiting non-Newtonian viscosity properties. It is there said that any thixotropic or pseudo-plastic fluid, such as polymer solutions, gels, and emulsions, with suitable pumping characteristics and which can suspend bulk solids may be used. High internal phase emulsions where the internal phase is a major part of the emulsion were found to be particularly well suited for this use. In Republic of South African Pat. No. 741835, there is disclosed a fuel composition that may be transported through a pipeline. The fuel composition is a combustible slurry including coal and methanol. The coal is in particles of critical and sufficiently small size to tend to remain in suspension in the slurry instead of separating out. In U.S. Pat. No. 3,968,999, there is described a method of transporting a slurry of coal and methanol through pipelines in arctic environments without melting the permafrost of the environment. Methanol is cooled to a temperature of less than 32.degree. F. and particulate coal of a size less than 200 mesh is mixed therewith to form a coal combustible mixture and the coal combustible mixture is pumped through the pipeline. There is described in U.S. Pat. No. 3,926,203 a method of transporting crude oil or tars recovered from arctic areas through a pipeline in the arctic areas in the form of an oil dispersion in a methanol or a methanol-water dispersing medium. Preferably a surface active agent is provided in the oil-methanol or oil-methanol-water systems to better provide a satisfactory dispersion of the oil in the dispersing medium. In a described aspect of the invention, natural gases produced along with the crude oil or otherwise recovered may be converted to methanol for use as a dispersing medium.
In U.S. Pat. No. 3,950,034, there is described a method of pipelining solids by suspending the solids in a liquid containing lamellar micelles and pumping the mixture at flow rates predetermined to produce retro-viscous behavior in the liquid at noncryogenic temperatures. The liquid is a composition containing a surfactant, preferably a petroleum sulfonate and at least two substantially immiscible liquids, such as liquid hydrocarbon and water, and optionally up to 20% of a cosurfactant, preferably an alcohol containing 1-20 carbon atoms and/or an electrolyte, preferably an inorganic salt. In U.S. Pat. No. 3,907,134, there is described a substantially water-free, high solid content, stable and combustible fuel slurry that is comprised of solid particulate carbonaceous material, such as powdered coal, a liquid hydrocarbon fuel, such as Bunker C fuel oil, a slurry suspension stabilizing agent, preferably starch, and a viscosity reducing agent, preferably a detergent.
In German Offenlegungsschrift No. 1558969 there is described a method of transporting solid particles through pipes in the form of a suspension in an aqueous carrier liquid, which carrier liquid contains an aromatic hydrocarbon sulfonate and an ethylene oxide polymeride with a high molecular weight for transfer of dilatant properties to the carrier liquid.
In U.S. Pat. No. 4,045,092 there is described a fuel composition that can be transported and stored. The fuel composition is characterized by a combustible, pseudothixotropic liquid-solid suspensoid including a critical proportion of coal particles having a critical settling velocity substantially uniformly dispersed in a solution of methyl fuel including methanol, water and other alcohol-soluble constituents of the coal. Additives may be employed to impart more nearly perfect shear thinning thixotropic rheological characteristics of the liquid-solid suspensoid.